The present invention relates to an automobile spider type wheel made of aluminum alloys and having a face layer of stainless steel. The face layer is formed on one side of a stainless steel insert which is worked by a press process. When the spider wheel is cast by a die casting process the casting material is integrally molded on the faces on the other side of the spider wheel whereby the external appearance of the resulting spider wheel is made beautiful and easy to clean.
In addition, the present invention relates to a process for manufacturing the automobile spider wheel. Automobile wheels include disc type wheels as well as spider wheels. The present invention may be applied to a disc wheel as well as the spider wheel of the invention.
In general, a spider wheel for automobiles comprises a rim which supports a tire and a hub. The hub is formed with a hub axle hole which receives the axle and a number of hub nut holes which fix the wheel to the axle. A number of rim supports are radially formed between the hub and a rim base.
In order to facilitate reduction of weight in the wheel and cooling during the production of heat by a brake drum, the spider wheel formed holes between the rim supports have mainly been used.
The automobile spider wheels with tires must allot and support the entire weight of the automobile and must bear up against torques during driving and braking, impulse forces on the road, centripetal forces in rotation and forces in the side direction produced in slanting or turning the automobile. The spider wheels must have light weight and reduce the retention of heat.
Accordingly, materials for conventional automobile wheels have aluminum alloys as casting alloys. The aluminum alloys used include A356 alloys which comprise Al as a main component and can include Mg, Si, Sr, Ti and Fe as minor components, AM alloys and SAM alloys having Mg and Si in different amounts.
Conventional automobile wheels which use the aluminum alloys have been made by a die casting process, which is simple and possible for mass production, or by a combined process which combines the die casting process with a spinning process to provide high strength and high toughness.
However, the automobile wheels made of aluminum alloys which are cast by the die casting process have faces with an external appearance that does not look attractive. In addition, when faces of the wheels have adhered thereto contaminants, such as fine soils, dust, oils and the like, there is much difficulty in washing the contaminants.
Further, in a modified wheel for automobiles, the wheel has been worked to have a smooth face and then has been plated with cromium. The wheel with Cr plating looks fine in external appearance on the face thereof, and is easily washed. However, when the wheel with Cr plating is manufactured, a surface working process or a plating process is supplemented and manufacturing costs such as working cost, making cost and labor cost are highly increased, and many process hours are required to manufacture the wheel. Accordingly, in mass production for the wheels there are various technical problems and cost problems.
An object of the present invention is to provide an automobile spider wheel of aluminum alloys with a face layer formed as a stainless steel insert to overcome drawbacks of the prior art.
Another object of the present invention is to provide an automobile spider wheel made of an aluminum alloy or alloys, and having a face layer of a stainless steel material at least on the viewable portion of the wheel. A stainless steel insert is worked by a press process based on side face shapes of an automobile wheel to provide wrapped faces for a rim, and faces for a hub and rim supports with holes formed between the rim supports of the automobile wheel. The faces provide the external appearance of the wheel when a tire is mounted thereto and the wheel is secured to a vehicle. On an opposing side of the stainless steel insert, the faces for joining with a melted aluminum alloy are treated roughly by sanding or brushing. A plurality of supporting protrusions are weldably fixed on the joining surfaces of the insert in positions corresponding to rim support faces of the wheel. The insert is placed on a bottom of a lower mold of a molding device with the protrusions projecting upwardly. The side face of the insert having the joining surface is integrally molded to the wheel formed of at least one aluminum alloy by a die casting process after assembling left and right molds and an upper mold of the molding device. The protrusions are then embedded in the aluminum alloy. The faces of the insert contacting the lower mold remains as stainless steel.
Further, an object of the present invention is to provide an automobile spider wheel of aluminum alloy with a face layer of stainless steel so that smoothness, brightness, easy cleaning and beautiful external appearance on the viewable faces of the wheel are provided without any plating treatment due to the stainless steel insert properties having high brightness, corrosion resistance and heat resistance.
Embodiments for the spider wheel and a process for manufacturing the wheel will be explained according to the drawings in greater detail.